Casing for air filters



May 4, 1954 A. MAzEK CASING FOR AIR FILTERS 2 Sheets-Sheet l Filed Aug. 29, 1952 @mlm @www m m INVENTOR fiar/rela Muzi/ BY 7M M0144 l ,ATTORNEYS w May 4, 1954 A. MAzEK CASING FOR AIR FILTERS Filed Ag. 29, 1952 @if @w32 @.7

2 Sheets-Sheet 2 ATTORN EYS Patented May 4, 1954 UNITED STATES TENT OFFICE `CASINGr FOR AIR FILTERS Application August 29, 1952, Serial No. 307,043

(Cl. l83--49) 3 Claims.

This invention relates to an improved air filter of the type which employs a mass of porous material for the filtering medium.

With air nlters of this type the mass of filtering material is ordinarily held in a four-sided open framework of paper chipboard or the like which has a skeletonized network across the two open faces of the framework. In use the pressure of the air iiow pushes the downstream side of the framework against its supporting members and this provides an air seal so that the air is forced to pass through the ltering material. In order to achieve an effective air seal, the framework must have dimensional stability. It must be strong enough to withstand shipment and handling without distortion and it must also resist warping in the moisture cf the air. If the casing is warped or distorted, it cannot be pushed flat against the supporting members and the air bypasses the filtering material.

In carrying out my invention I provide a framework made of reinforced I-beams which are butted together in the framework to give an extremely light but rigid structure which has proven strong enough in use to withstand shipment and handling without distortion. My I- beams show no appreciable warping throughout the useful life of the filtering medium and as a result the filter framework gives a highly effective air seal with its supporting members.

Further advantages of my invention may be readily understood by reference to the accompanying drawings in which Fig. 1 shows a plan view of my improved air lter casing; Fig. 2 is a side view of Fig. l with a portion of the casing cut away to show the filtering medium; Fig. 3 is an isometric view of a corner of the casing which illustrates its construction; Figs. 4, 5, 6 and 7 show blanks of material such as paper chipboard or the like which may be used for making my reinforced Iii-beams; Figs. 8, 9 and 10 show modifications in the construction of my air filter; and

l1 shows a modified form of I-beam.

In the drawings the numeral l@ indicates an air filter made in accordance with the present invention. As shown, the framework or casing is made of reinforced I-beains i2 which in turn are made from the blanks of Fig. 4. This is done by cutting the material to the form shown after which both sides of the material are folded along the lines of scoring il and the top section on each side is folded downwardly along the lines of scoring l5. The I-beam so produced (Fig. 3) is reinforced by the double thickness of material running across approximately one half of the width of the cross flanges lli and this double thickness also provides a pocket 2@ which receives the cross flanges of the adjoining I-bearn. A section is cut out of each end portion of the web 22 as indicated at 2li so that the beams may be butted against each other in the finished casing. The I- beams are assembled in the casing as shown in Figs. 1, 2 and 3.

After three of the beams have been assembled a skeletonized wire network 25 is inserted into pockets 2t across the open face on each side of the casing and a section of the filtering medium 2l is inserted between the wire networks. As shown in the drawings I prefer to use a fluffy mass of glass bers as the ltering medium but any other bulky filtering medium may be used such as an open work mass of plastic fibers or the like. 'Ihe fourth I-beam is then placed in position to complete the casing. If desired a center support 28 may be positioned across the wire network to reinforce it.

Any convenient means such as a suitable liquid adhesive, gummed tape, staples, or rivets may be used for holding the wire network in pockets 2@ and the I-beams in position in the casing. However, for maximum strength I prefer to use a liquid adhesive which is applied in a continuous line along the inside of each pocket 2E) and on the unexposed portions of flange l5 as indicated at 30. Since the grain in adjacent layers of material is crossed the I-beams of my construction are extremely rigid and they show great resistance toward bending in any direction. Pockets 2t provide a firm anchorage for wire network 2t and as a result the wire assists in maintaining the sides of the framework in parallel relationship which is extremely important for industrial use where the individual iilters are iitted together in a bank.

In the preferred form of my invention shown, web 22 of the I-beams is positioned approximately at the center line along the length of cross iianges E3 in order to give the cross flanges maximum support against the thrust of the air stream. It will also be noted that for a given size filter casing this reduces the size of the enclosure so that less filtering material may be used to lill the casing.

Figs. 8, 9 and l0 show modified forms of air iilters made from the blanks shown in Figs. 5, 6 and 7. rEhe I-beams are made from the blanks shown in these figures in the same way as above described for the blanks shown in Fig. 4:. The air lter casing shown in Fig. 8 is assembled by using two of the I-beams made with the blank of Fig.

4 and two made with the blank of Fig. 5. The advantage of this construction is that the center flanges 22 of the I-beams of Fig. 5 extend out to the edge of the casing and this reinforces the corner which is important for industrial installations where the air lilters are held in bank by spring clips at each corner. The same type of construction is shown in Fig. 9 except that I- eeains made with the material of Fig. 6 are used in place of the I-beams of Fig. 5. In this construction end flap 32 of the center web is positioned outwardly at a diagonal across the corner of the casing. As shown in Fig. l the casing may be assembled with four of the I-bearns made of the material oi Fig. 6. When this is done one end iiap 32 may be extended diagonally under the corner of the casing and the other folded inwardly along the surface of the center flange of the adjoining I-beam. This construction is used where an air lter with especially strong corners is needed. The material shown in Fig. is used where an I-beam having a strong center flange is required. The blank shown in Fig. 'i is folded along the lines of scoring as described above to make one-half of the I-beam of Fig. ll. As shown, the center web 22 is made by overlapping sections of the material and these sections may be laminated together with a suitable adhesive, staples or the like. Of course the end portion oi the center web of the I-beam of Fig. l2 may be cut as shown in Figs. 4 and 6 to make the filter casings of Figs. 9, 10 and 1l. have mentioned the use of paper chipboard as a material of construction, but other suitable materials such as resin bonded chipboard paper, impregnated plywood or light gauge metals may also be used.

It will be understood that it is intended to cover all changes and modications of the examples of the invention herein chosen for the purpose of illustration which do not constitute departures from the spiirt and scope of the invention.

What I claim is:

i. In combination with air filtering material, an air lter casing for said material comprising a tour-sided open framework having sides of reinforced -beams which are butted against each other in the framework to give a light but rigid structure having two open faces and a skeletonized wire network positioned across each or" said open faces in which each I-beam comprises a center web having a pair of oppositely disposed cross flanges positioned along the top and bottom edges thereof which extend outwardly from the exterior surface of the web at an angle of approximately 90 and which are doubled back on themselves and extended inwardly beyond the interior surface of the web to increase the strength of the ange and prevent it from warping during use and to form a longitudinal pocket opening into the interior of the casing which contains an edge portion of one of said. Wire networks, two of said I-beams having cross-anges which are extended in a longitudinal direction out beyond each end edge of the web, which longitudinally extended end portions are positioned in the pocket of the remaining two adjacent I-beams in the assembled casing in an abutting relationship to give the casing rigidity and dimensional stability.

2. A structure as speciied in claim l in which the end portion of the web of the remaining two adjacent I-beams is detached from said crossllanges to form a ap at either end of the said I-beams which extends diagonally out to the corner of the casing and reinforces it.

3. In combination with air nltering material, an air lter casing for said material comprising a four-sided open framework having sides of reinforced I-beams which are butted against each other in the framework to give a light 'ont rigid structure having two open faces and a skeletonized wire network positioned across each of said open faces, in which each I-beam comprises a center web having a pair of oppositely disposed crossflanges positioned along the top and bottomedges thereof which extend outwardly from the exterior surface of the web at an angle of approximately and which are doubled back on themselves and extended inwardly beyond the interior surface of the web to increase the strength of the liange and guard against warping during use and to form a longitudinal pocket on the interior or the casing which contains an edge portion of one of said wire networks and said cross-flanges being extended in a longitudinal direction beyond each end edge of the web to form a pocket beyond such end edges, said longitudinally extended end portions of two of said cross-flanges being positioned in the pocket formed by the corresponding longitudinally extended end portion of the remaining two adjacent I-beams, in an abutting relationship to give the casing rigidity and dimensional stability.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,598,097 Mathis Aug. 31, 1925 2,020,120 Leathers Nov. 5I 1935 2,567,030 Schaaf Sept. 4J 1951 

